<%= simple_form_for([@post, @post.comments.build]) do |f| %>
<!--
collection.build(attributes = {}, …) Returns one or more new objects of the collection type that have been instantiated with attributes and linked to this object through a foreign key, but have not yet been saved. Note: This only works if an associated object already exists, not if it‘s nil!
-->
<div class="field">
  <div class="control">
    <%= f.input :name, input_html: { class: 'input' }, wrapper: false, label_html: { class: 'label' } %>
  </div>
</div>

<div class="field">
  <div class="control">
    <%= f.input :comment, input_html: { class: 'textarea' }, wrapper: false, label_html: { class: 'label' }  %>
  </div>
</div>
<%= f.button :submit, 'Reply', class: "button is-primary" %>
<% end %>
